Pomeranz will be used as a reliever in the postseason if he is on the roster.
Boston's postseason rotation will include Rick Porcello, David Price, Eduardo Rodriguez and Clay Buchholz if manager John Farrell elects to go with four starters.
"The forearm area is where he's experiencing some of that discomfort. He needs a few extra days," said Farrell. "So combined with his career high in innings pitched -- I think he's roughly at 170 innings -- we're backing him out of his last start. We need to get him on a mound hopefully by the end of the week to determine a bullpen role going forward.